Why AVRFreaks members do not like XMEGA

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#1
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Hi all,

I have spent hundreds of hours studying XMEGA and I did several tests on this family and found tens of errors in Atmel datasheets and app notes.
But as I see, AVRFreaks members are not so interested on XMEGA.
The question is why?

Ozhan KD
Knowledge is POWER

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I don't like they split the data sheet in two: one describing a family, the other for a specific part. I always don't know in which one I will find what I want to know (register names, addresses etc), so I have almost always to look in both of them. Maybe it is only me.

The old stile I like, everything in one document.

George.

www.sofgel.ro bootloader for mega and xmega
www.elsofgel.com XME development board

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It's not popular with people here because of the hardware bugs and the complexity of the device, compared with the AVR.

Leon Heller
G1HSM

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That is why the devices should be called compleXMEGAS then? :lol

Jim

I would rather attempt something great and fail, than to attempt nothing and succeed. - Fortune cookie

 

Don't hang your hat on expectations because this often leads to disappointment.

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Quote:

It's not popular with people here because of the hardware bugs and the complexity of the device, compared with the AVR.

I think it might have caught on more, or at least faster, if:
-- there hadn't been the >>years<< delay until parts became somewhat available
-- the extensive errata list, that did not get cleaned up over a number of silicon revisions

Complexity? Plain-vanilla stuff isn't too much more than the AVR, IMO. But you have a lot more features/flexibility. So you have to specify, and configure the I/O registers to use the features.

I 9and others) were very excited when the announcement came out. Leon has participated in many discussions of "better" micros than the classic AVR. I saw the Xmega as an intermediate step between the classic AVR and moving to ARM or other totally different family.

Many of the "complex" features are ARM-like. At least akin to the features in the SAM7S ARM7TDMI I was considering before the Cortex took off. This is the crux of the problem, IMO: these Xmega features were announced, but by the time they came to [buggy and spotty availability] fruition, a couple of generations of Cortex are on the scene. The window was missed, at least for me. Perhaps I might nibble if the devices become stable and with a manageable errata list.

A short list: 12-bit fast[er] ADC; couple of DAC channels; DMA; advanced interrupt controller; enhanced ports; more/more flexible timers and USARTs. Then compare to Atmel's own SAM7S models--the subsystems mentioned look substantially the same. So why is e.g. ADC so crappy over several silicon revs, when Atmel already had it stable and in production? Same with the flash read speed problems.

The "family" doc plus the model-specific datasheet is very common nowadays; I wouldn't criticize that.

You can put lipstick on a pig, but it is still a pig.

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They could have done quite well, but Atmel seems to have given up on them.

I actually bought a few chips and was thinking of using them, but discretion being the better part of valour, I abandoned the idea.

Leon Heller
G1HSM

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XMEGA and PIC32 make no sense to me, given the plethora of suppliers for ARM7/9/Cortex.

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The MIPS processor used in the PIC32 has several advantages over the ARM. They are pin-compatible with the larger 16-bit PICs, and use the same peripherals, making it easy to increase the performance of a system without a hardware redesign.

Leon Heller
G1HSM

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Quote:
AVRFreaks members are not so interested on XMEGA.

It could be, also, that as is often the case the complainers are speaking out, and very visible & vocal, while those that have adopted it are simply getting on with what they are doing.

I happen to like the Xmega, and it is my chip-of-choice these days, unless I am using a Tiny as a front end processor. That said for a recent project that I had anticipated using an Xmega for I ended up using a Mega with its trouble free ADC instead of the Xmega and an external ADC.

But I buy uCs 10 at a time, not 10K at a time, so my impact on the series' long term market share and success is minimal.

JC

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electronic.designer wrote:
But as I see, AVRFreaks members are not so interested on XMEGA.
The question is why?
Oh, people were excited about it - until they found out the truth.

It started with a press release in February 2008. There some Atmel marketing guy claimed something like "immediate available". However, mere mortals couldn't get one for a year or longer. In the meantime Atmel managed to *cough* convince *cough* a trade rag to declare this vapourware "Product of the year". Then Atmel came out with an eval board, the Xplain. Only that you couldn't buy it, you had to take part in some exclusive seminar.

People were literally begging Atmel to sell them an eval board or just an Xmega. Atmel didn't care. In fact, Atmel didn't care to communicate at all about the Xmega, except listing more and more Xmega variants on their website, non being available.

And when people could finally get some Xmegas it turned out they were badly broken (AFAIR rev. G of the 128A1). Then the next revision (AFAIK rev. H) came out, still badly broken.

The Errata list is growing ever since. And IMHO it is still incomplete. E.g. I think the fact that a good bunch of Xmegas came (or still come?) with no calibration data in the calibration row isn't mentioned.

I can say that whatever part of the Xmega I touched, it turned out to be broken after I spent a lot of time to get it working. Until I gave up on the Xmega.

And of course, Atmel isn't communicating. People are stuck with the broken revision, and no word or information when, if at all, Atmel intends to fix some issues.

Also, it took a long time until Atmel added Xmega programming support to their garden-variety programmers. The Dragon's PDI support is still limited to a few Xmega models. And Atmel didn't and doesn't communicate about that.

When people here asked for an Xmega forum, they didn't get one. What we got was a useless security products forum. Atmel quickly abandoned that forum, when it didn't result in the intended burst of sales (hint: What good is a forum for products one can't buy from normal distributors?).

This ridiculous ASF library is also not helping. For some time people were literally begging Atmel to release the complete source code of the Xplain software. AFAIK it still isn't available. Instead we got a strange "xplain software framework 1.0", and later the ASF.

There is probably more that Atmel did wrong. It is a kind of textbook case of what not to do. It is not that people hate the Xmega. It is Atmel hating small-fish developers and don't giving a ...

Stealing Proteus doesn't make you an engineer.

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I would have started to use some if they came in pin compatible pinout with some Mega chips ie drop 1 into an exiting boards. But then they don't work at 5V so it's a complete redesign, more stock to keep etc.

I havent't needed the power of anything more than a mega running at 1/3 of maximum speed yet, but I could have used the "better" ADC and definetely more serial ports it offers. Otherwise bahhh humbug... :lol:

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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